1. Field of the Invention
The present invention relates generally to stent graft selection, and more particularly to computer based systems and methods for stent-graft selection.
2. Description of Related Art
Intraluminal devices are known for treating stenosis, stricture, aneurysms and the like. Intraluminal or endoprosthetic grafts are designed as internal bypass devices, which relieve stress from the surrounding vessel wall. Often, a device of this type is percutaneously implanted within the vascular system to reinforce collapsing, partially occluded, weakened or abnormally dilated localized sections of a blood vessel.
The need for repair of an abdominal aortic aneurysm in patients has been recognized for many years. Surgical repair of an abdominal aortic aneurysm has a much higher mortality rate than less invasive techniques using a stent graft.
Typically, in choosing a stent graft for repair of an abdominal aortic aneurysm, a pre-operative imaging modality is used. The four most utilized imaging modalities are contrast aortography (CA), spiral computed tomography (CT), magnetic resonance imaging (MR), and intravascular ultrasonography (IVUS). A physician uses the image to assess the diameter of the aneurysmal portions of the aortic system, the diameter and length of the non-aneurysmal proximal neck for anchoring the stent, the diameter and length of the distal aortic/iliac neck, and the total length of the prosthesis required for spanning the length of the aneurysm with fixation into normal arterial tissue proximally and distally of the aneurysm.
With these measurements, the physician uses information provided concerning a particular stent graft to select a stent graft for a particular patient. The selection of the appropriate stent graft is crucial for a successful treatment. Many factors complicate this selection.
For example, a certain length of a normal arterial segment has to be present to anchor the stent graft. If such a segment is not present, no stent graft should be placed. Most stent grafts stay in place because they are larger in diameter than the native vessel, therefore a certain amount of over sizing is necessary. However, too much over sizing can lead to redundance of the cover material and lead to leakage or narrowing.
A failure to consider one of these factors or an inadvertent error in translating a dimension from the image to a device size can result in selection of an inappropriate stent graft. Similarly, an error is entering measured data on an order form can result in the physician obtaining an inappropriate stent graft. In addition, there is no feedback to the physician concerning the accuracy of the measurements take from the imaging or the relationship of the stent-graft selected to the patient's arteries until the placement is in progress.
Also, the stent graft technology is constantly evolving and the number of stent grafts available is increasing and will continue to increase. These factors further complicate the selection of the best stent graft for the patient.